The Adventure of the Ring of Stones — James P. Blaylock

The secret log of a murdered lighthouse keeper falls into the hands of the immensely wealthy Gilbert Frobisher, who discovers encoded within it a stunning and dangerous mystery.

Against all odds Langdon St. Ives and his companions set sail in the dark of night for the West Indies aboard Gilbert Frobisher s steam yacht, pursued by murderous pirates and bound for an uncharted volcanic island on the verge of eruption. There they undertake the perilous search for a hidden treasure protected by an unspeakable pagan god, and in the process unleash a power that will ultimately threaten the devastation of London.